AXPZ20 KNHC 232202
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
2205 UTC Sat Jun 23 2018
Tropical Weather Discussion for the eastern Pacific Ocean from
the Equator to 32N, east of 140W. The following information is
based on satellite imagery, weather observations, radar, and
Based on 1800 UTC surface analysis and satellite imagery through
...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
The monsoon trough extends from 10N75W TO 09.5N85W to 1010 mb
low pressure near 14N106W to 1008mb low pressure near
12.5N115.5W to 09N122W. The ITCZ continues from 09N122W to
08N128W to beyond 11.5N140W. Scattered to locally numerous
moderate to strong convection is noted from 04N to 12N east of
97W to the coast of Colombia. Scattered moderate to strong
convection is noted within 210 nm either side of the trough
between 98W and 120W, and from 04N to 12N between 129W and 138W.
OFFSHORE WATERS WITHIN 250 NM OF MEXICO...
NW winds have generally diminished across the offshore waters
west of Baja California, as a broad surface trough along the W
coast of the peninsula has shifted westward and farther away
from the peninsula. Afternoon observations along the coast
indicate that daytime heating has lead to seabreezes to around
15 kt have developed along the coastlines. Winds will remain
variable 10 kt or less through the weekend offshore and be
dominated by land and sea breezes near the coast. Southerly
winds inside the northern Gulf of California were captured by a
midday ASCAT pass and showed 20-27 kt to the north of 28N, while
fresh to strong winds are expected elsewhere N of 26N this
afternoon. Seas have increased to 6-9 ft north of the Tiburon
Basin, and are 4-7 ft south of there. Winds and seas will begin
to slowly subside later tonight through late Sunday.
Further south, long period cross-equatorial SW swell continues
to gradually build across the regional waters and will affect
the waters from central Baja California to Central America
through Monday. 5 to 7 ft seas off of Southern Mexico today will
build to 6-8 ft by Sun morning before slowly subsiding late Sun
night and Mon.
OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND
WITHIN 750 NM OF ECUADOR...
The monsoon trough will meander between 09N and 13N the next
several days. Light to gentle winds will prevail north of the
monsoon trough, with gentle to moderate S to SW winds expected
south of the trough axis. Long period cross-equatorial SW swell
has moved into the regional waters and will gradually build
across southern forecast waters through Sun, and peak near t 7-
9 ft tonight, then will gradually subside Sun through Mon.
A tropical wave across Central America along about 90W will
continue westward through Mon and maintain active convection
near and to the south of the monsoon trough during this time.
REMAINDER OF THE AREA...
High pressure north of the area centered near 35N141W extends a
ridge SE to near the Revillagigedo Islands. To the S and SE of
the ridge, moderate to fresh NE to E winds prevail west of 130W
with seas generally ranging between 5 to 7 ft. Gentle to
moderate N to NE winds dominate the remainder of the basin north
of the monsoon trough and west of 120W. The high pressure center
is forecast to shift NW and reorganize, while the weak trough
offshore of Baja California drifts west to near 120W through
Mon. This will gradually freshen winds N of 25N and to the west
of 125W, producing NE winds of 15-25 kt, and building seas of 7-
10 ft across the northern waters.
Typical northerly swell generated offshore of California is
propagating into the northern waters today, and will build seas
modestly to 8 ft north of 28.5N between 122W and 129W late
tonight before seas subside to 6-7 ft Sun afternoon. The cross-
equatorial southerly swell is also moving through the tropical
waters south of 20N and west of 120W today, and will maintain
seas 5-7 ft there through Mon.
A low pressure centered near 12.5N115.5W embedded along the
monsoon trough has an estimated pressure of 1008 mb. Model
guidance shows this low drifting northward with a gradual
increase in intensity through the weekend. Active thunderstorms
will continue in the vicinity of this low through early next
week before the low moves across cooler waters and begins to
weaken considerably Tue.
A 1010 mb low pressure is near 14N106W generating scattered
moderate to strong convection from 11N to 17.5N between 99W and
110W. Global models indicate that this low will linger across
this area through at least Mon and continue to generate active